Allow the default generic font family settings to find the first available font

ui/gfx/font_list_unittest.cc

Index: ui/gfx/font_list_unittest.cc
diff --git a/ui/gfx/font_list_unittest.cc b/ui/gfx/font_list_unittest.cc
index 770e23e5ae3a9d3891dfec1b475a9222ebd96f3f..0d8bda779380eaa2084af599b904d95507148b5f 100644
--- a/ui/gfx/font_list_unittest.cc
+++ b/ui/gfx/font_list_unittest.cc
@@ -356,4 +356,24 @@ TEST(FontListTest, MAYBE_Fonts_DeriveWithHeightUpperBound) {
   EXPECT_EQ(font_list.GetFontSize(), derived_2.GetFontSize());
 }
 
+TEST(FontListTest, FirstAvailableOrFirst) {
+  EXPECT_TRUE(FontList::FirstAvailableOrFirst("").empty());
+  EXPECT_TRUE(FontList::FirstAvailableOrFirst(std::string()).empty());
+
+  EXPECT_EQ("Arial", FontList::FirstAvailableOrFirst("Arial"));
+  EXPECT_EQ("not exist", FontList::FirstAvailableOrFirst("not exist"));
+
+  EXPECT_EQ("Arial", FontList::FirstAvailableOrFirst("Arial, not exist"));
+  EXPECT_EQ("Arial", FontList::FirstAvailableOrFirst("not exist, Arial"));
+  EXPECT_EQ("Arial",
+            FontList::FirstAvailableOrFirst("not exist, Arial, not exist"));
+
+  EXPECT_EQ("not exist",
+            FontList::FirstAvailableOrFirst("not exist, not exist 2"));
+
+  EXPECT_EQ("Arial", FontList::FirstAvailableOrFirst(", not exist, Arial"));
+  EXPECT_EQ("not exist",
+            FontList::FirstAvailableOrFirst(", not exist, not exist"));
+}
+
 }  // namespace gfx